Coupling transformer



Rdarch 2 ,1926.

w. J. DOW COUPLING TRANSFORMER Filed April 3, 1924 nltlllllm. 2 7

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lill! m Patented Mar. 2, 1926.

UNiTED STATES PATENT OFFICE.

WILLIAM J. DOW, 0F WASHINGTON, DISTRICT 0F COLUMBIA.

COUPLING TRANSFORMER.

Application filed April 3, 1924. Serial No. 704,071.

To all whom t may concern.'

Be it known that I,\VILLIAM J. Dow, a citizen of .the United-States, residing at Washington, in the District of Columbia, have invented certain new and useful Im- .provements in Coupling Transformers, of

which the following is a specification.

This invention relates. to coupling transformers and more particularly to a coupling device for -use between two electric circuits of a radio receiving apparatus `where small amounts of energy are utilized to transmit signals. y

n the operation of radio receiving apparat-us usually employed in various circuits used with crystal .or 'tube detectors and including both regenerative and non-regenerative types and audioor radio frequency amplification where energy transference from one circuit to another is effected through electro-magnetic coupling, much difficulty has been experienced in obtaining f a suitable degree of selectivity of the apparatus throughout a wide range of wave .lengths of vthe signals. This difficulty has been largely due to the fact that the external magnetic field produced about the coupling coils has caused magnetic disturbances which affects the neighboring apparatus and prevents the coupler or transformer from functioning with the proper and desired selectivity.

`An object. of this invention contemplates a novel winding which confines the magneticfield in such a manner that magnetic leakage.

inthe neighborhood of the coil will be practically zero.

Another object of this invention consists in the provision of a novel type of coupling transformer for v.use in radio circuits in which the coupling may be as tight or loose as desired and yet in which there is substantially no external magnetic field.

These andother features and advantages of the invention appear more fully from the detailed description when read in connection with the accompanying 'drawings and pointed out in the appended claims.

In thed'rawing:

Figure lis a perspective View of a coupling transformer constructed in accordance with this invention;

Fig. 2 is a perspective view showing modified, core sections se arated and the coilsmounted thereon; an

lmay be composed' of bakelite or other suitable insulating material. While the core 11 ma be of anyconvenient shape, I prefera ly employ two sections 12 and 13 which give the transformer a cylindrical configuration. These sections are secured in spaced relation by suitable bands 14 and 15 placed at the upper and lower portions of the core sections.

Upon the core vsections 12 and 13 are mounted the windings of the primary and secondary circuits which are wound so that substantially no external magnetic fields of force. will bc set up in the vicinity of the coil. As shown, a coil comprising the primary circuit consists of a suitable nimibei' of turns of wire 16 coiled around the top portion ot' section 12. and connections to this coil are afforded by binding posts 17 and 18, respectively. In a like manner, an equal number of turns 19 are coiled around the bottom portion of the adjacent D-shaped section 13, and connections to this coil section are afforded by binding posts 20 and 21. These two coils may be connected in series as shown and the arrangement is such that the coil sections 16 and 19 which form the primary circuit are wound in oppositey directions so that at any one instant the di- .oppositely wound, and preferably connect-ed in series therewith. consists of an equal number ot turns coiled around the bottom portion of section 12 opposite the primary section 19. This portion of the coil is also provided with binding posts 26 and 27. Any number of primary and secondary sections may be used, the arrangement being such that the coils ofthe secondary circuit may be said to interleave with corresponding, coils of the primary circuit. j

The diagrammatic representa-tion. of the coil illustrated in Fig.l 3 shows the coils in their relative positions and in. order that the ratio of the turns may be variable, adjustable contact riders 28 and 29 are provided on a portion of the primary and secondary coils.

In effect the coils of the transformer are in staggcr-relation so that the coil portions on eac-h core su port are alternately primary and secon ary windings. It will be noted that from this interrelationof the coils with respect to each other a substantial ma netic field will traverse the coil sections w ien an electric current traverses one of the coils of the coupling transformer, the magnetic lines `of force following a substantially elliptical closed circuit, the external circuit of the field of force beingl thus materially .reduced This result is particularly necessary and 'advantageous in the operation of radio apparatus where great care must he exercised to prevent adjacent apparatus from beiner affected by electrical disturbances Vwhic are inherent in the usual apparatus.

This is particularly true in the operation of fixed. couplings in' a radio receiving. apparatus where lit is desirable to .obtain a great degree of selectivity of the incoming or transferred si nal and the success of the reception of the signal depends to a large extent-upon the proper ratio of the w1n d1ngs of the primary and secondary `circuits as well asthe ability of the instrument to be free from the electric disturbances set up 1n adjacent apparatus' l-v-'hile-but one modification has been disclosed, it is to be understood that the inf vention may take various forms and it is desired that it shall only be limited by the scope of the appended claims.

`What I claim is: I 1. A coupling transformer liavingprimary'and secondary .windings comprising a pair of insulation cores having their axes parallel, a section of one of said windings .on each core at axially displaced positions,

said sections being wound in opposite directions, and a portion of said other winding on one of said cores. j 2. A coupling transformer having primary andsecondaryg windings comprising a pair of insulation cores having their axes parallel, a section of one of said windings on each core 'at axially displaced positions,

lsaid sections being wound in opposite directions, and a portion of said other` winding air on each core at axially displaced positions',

said sections beino' wound in opposite directions, and aportion of said other winding on each of said cores adjacent one of said first mentioned sections.

5. 'A upling transformer' having primary and secondar windings comprising a pair of parallel a jacent insulation cores, one of said windings being divided between said cores in staggered oppositely wound'V sections,- said other winding being interposed beside said sections and inductively coupled to said first mentioned winding. 6. A coupling transformer for radio systems comprising a primary ,anda secondary Q winding, the turns of each winding being divided into groups and staggered to bring alternate groups of one winding into alinement with aternate groups of the other winding, the adjacent groups of each winding being oppositely wound.

In a transformer, a. primary and a. secondary winding, each winding comprising two sections, a section of one winding in axial 'alinement with a sec-tion of the other winding and consti-tuting a pair and arranged parallel to the other pair of sections, the sections of one winding arranged in ofi'- set relation to the'sections .of the other pair and connections between the sections of each winding.

8. In a transformer, a primary and a secondary winding, each wmdingcomprisingtwo sections said sections arranged in axially alined pairs, one pair parallel with the other each pair comprising a section of each windi arranged in offset relation, and connections tween the two sectionsof each winding. j

9. A coupling .transformer comprising a primary and a secondary winding, the turns of each winding being divided into groups, the adjacent ones of which are wound in opposite' directions and the alternate groups of each winding being offset laterally to aline with the offset groups of the other winding.

In testimony whereof I aiiix my signature. 

